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1.
In the Japanese warm areas, as a result of intensive and repeated potato cropping, common scab, a soil-borne disease has become a serious problem. The soil moisture level has been shown to be an important factor affecting the incidence of common scab. That is, a high level of soil moisture reduces the severity of common scab. However, in this investigation, although during the spring cropping precipitation was abundant, a large number of tubers showing scab lesions were produced. The results indicate that the soil moisture level may not be an important factor affecting the incidence of potato scab in the humid region.

To identify other factors which may affect scab severity, the relation between sugar content in the peel of potato tuber and the incidence of common scab was investigated. Generally, the amount of reducing sugar in the tuber peel increased gradually with the growth of the tubers, then reached a maximum level two weeks after the start of tuber formation, and thereafter declined. The period corresponding to the highest sugar content in peels coincided with the most susceptible period for scab infection. The content of reducing sugar in the peel of susceptible cultivars was higher than that of the resistant cultivars, throughout the tuber growth, and the critical value of the content was 2.0 mg per 100 g fresh peel. These results suggest that the content of reducing sugar in tuber peel may be an important factor affecting the incidence of common scab.  相似文献   
2.
Cytochrome P450 proteins play important roles in plant herbicide selectivity. Here, we demonstrate metabolism of the herbicide pelargonic acid by CYP72A18, a novel cytochrome P450 isolated from the rice Oryza sativa L. cv. Nipponbare. The CYP72A18 cDNA was cloned from rice and heterologously expressed in Saccharomyces cerevisiae AH22 cells from the alcohol dehydrogenase (ADH1) promoter. Microsomes isolated from recombinant yeast cells contained the CYP72A18, which was found to catalyze the (ω-1)-hydroxylation of the herbicide pelargonic acid. We also show that (ω-1)-hydroxypelargonic acid has reduced herbicide activity against rice seedlings. Based on these results, we suggest that CYP72A18 participates in the detoxification of the herbicide pelargonic acid in rice plants.  相似文献   
3.
This study was designed to investigate whether supplementation of 2i medium with leukemia inhibitory factor (LIF) and/or forskolin would support establishment of germline-competent rat embryonic stem (ES) cell lines. Due to the higher likelihood of outgrowth rates, supplementation of forskolin with or without LIF contributed to the higher establishment efficiency of ES cell lines in the WDB strain. Germline transmission competency of the chimeric rats was not influenced by the profile of ES cell lines until their establishment. When the LIF/forskolin-supplemented 2i medium was used, the rat strain used as the blastocyst donor, such as the WI strain, was a possible factor negatively influencing the establishment efficiency of ES cell lines. Once ES cell lines were established, all lines were found to be germline-competent by a progeny test in chimeric rats. In conclusion, both LIF and forskolin are not essential but can play a beneficial role in the establishment of “genuine” rat ES cell lines.  相似文献   
4.
To help improve the use of models in science & policy analysis in Asia it is necessary to have a better understanding of model performance and uncertainties. Towards this goal an intercomparison exercise has been initiated as a collaborative study of scientists interested in long-range transport in East Asia. An overview of this study is presented in this paper. The study consists of a set of prescribed test calculations with carefully controlled experiments. Models used the same domain, emission inventory, model parameters, meteorological conditions, etc. Two periods (January and May 1993) were selected to reflect long-range transport conditions under two distinct seasons. During these periods measurements of sulfur concentrations and deposition were made throughout the study region using identical sampling and analysis protocols. The intercomparison activity consists of four tasks (Blind Test, Fixed Parameter Test, Source Receptor test, and Tuning Test). All participants were asked to do Task A, and as many of the other tasks as possible. To date seven different models have participated in this study. Results and key findings are presented.  相似文献   
5.
Through the use of a number of bioconversion experiments we demonstrated that P450 proteins (CYP1A9 and CYP1C1) from Japanese eel (Anguilla japonica) metabolized a number of herbicides and the drug phenacetin. We performed bioconversion experiments in which substrates were added directly to incubation medium. The resulting metabolites were extracted and analyzed by high-performance liquid chromatography. Proteins CYP1A9 and CYP1C1 metabolized 50 nmol of the drug phenacetin to yield 12.1 and 1.1 nmol of product (acetaminophen), respectively. Further incubation of CYP1A9 with 50 nmol of the herbicides chlorotoluron, diuron, linuron, simazine, or atrazine yielded 16.5, 18.5, 7.3, 1.6, or 0.8 nmol of product, respectively. CYP1C1 also metabolized linuron, diuron, and simazine yield 5.4, 4.6, or 0.7 nmol of product, respectively. Next, polyclonal antibody was isolated by immunizing with two conjugated-peptides (amino acid residues 272–290 and 294–310) of CYP1A9. This antibody did not recognize human CYP1A2 or CYP1C1. Western blotting using the antibody revealed one band in the livers of Japanese eel and tilapia (Oreochromis niloticus). Theses results suggest that CYP1A9 and CYP1C1 metabolize herbicides, and that CYP1A9 is an useful biomarker of contamination when detected with this antibody.  相似文献   
6.
Self-EcoTILLING to identify single-nucleotide mutations in multigene family   总被引:1,自引:0,他引:1  
TILLING (Targeting Induced Local Lesions IN Genomes) is a low-cost, high-throughput reverse genetic technique that employs a mismatch-specific endonuclease CEL-1 to discover induced point mutations in the genes of interest. The use of the TILLING technique to survey natural variation in genes is called EcoTILLING. Here, we report a modified EcoTILLING method for the discovery of mutations in multigene family, which we coin “Self-EcoTILLING” by using an allotetraploid Monochoria vaginalis ALS multigene family as an example. The mutations could be detected by TILLING of PCR products resulting from the primers specific to both Als1 and Als3 without involving the experimental step of mixture of reference and query DNA. Either of the two co-amplified loci could serve as reference DNA to the other. We demonstrate with this example that Self-EcoTILLING is a fast, reliable and economical technique of detecting single-nucleotide mutations in polyploid plants containing multigene family.  相似文献   
7.
We established a simple, rapid method for gizzerosine analysis in fish meal. Gizzerosine was extracted from fish meal with 0.1?N HCl solution. Samples and standard gizzerosine solutions were absorbed onto a paper disc, which was then set on electrophoresis paper for 18?min, and the paper was dried. Gizzerosine was visualized with Pauly??s reagent, and the intensity of the colored spots was digitized and calculated by image processing method software. We achieved successful separation of gizzerosine from other Pauly??s reagent-positive components in fish meal extracts. The linearity of gizzerosine estimation using this method was within the range 30?C1000?ng (R 2?=?0.99). Gizzerosine was satisfactorily detected and completely separated from histamine and other Pauly??s reagent-positive compounds. This method does not require expensive instruments or tedious pretreatment to eliminate interfering compounds, such as histamine or histidine. It also uses less reagent compared with high-performance liquid chromatography. Moreover, it is a simple, rapid, sensitive, and reproducible method. It is suitable for monitoring gizzerosine in fish meal products that contain as little as 10?ppm gizzerosine.  相似文献   
8.
To investigate the changes in microstructures of wood with elapsed time in the environment, CO2 adsorption onto dry wood was measured at ice-water temperature (273 K) for samples aged from 0.1 years to over 1000 years. The micropore size distribution was obtained using the Horvath-Kawazoe method. Micropores smaller than 0.6 nm in wood decreased in number with elapsed time in the environment, and a negative correlation was found between cumulative pore volume for pores smaller than 0.6 nm and elapsed time in the environment. Cumulative pore volume in the 1000-year sample was almost half of that in the 0.1- year sample. Micropores smaller than 0.6 nm in wood with a few decades or more of elapsed time increased in number after rewetting and drying. Consequently, microstructures of wood with longer time elapsed in the environment were considered to be more stable, because of longer-term thermal motion and possibly more repeated moisture adsorption and desorption and/or temperature variation in the environment.  相似文献   
9.
(3R)-Gobiusxanthin stereoisomers (1a–d) were synthesized by stereoselective Wittig reaction of the (3R)-C15-acetylenic tri-n-butylphosphonium salt 7 with C25-apocarotenal stereoisomers 5a,b and 14a,b bearing four kinds of 3,6-dihydroxy-ε-end groups. The validity of the reported stereochemistry of gobiusxanthin was demonstrated by the fact that the reported spectral data of natural gobiusxanthin were in agreement with those of synthetic (3R,3''S,6''R)-gobiusxanthin (1a). On the other hand, the reported CD spectral data of natural epigobiusxanthin, which has been assigned as (3R,3''R,6''R)-isomer (3''-epigobiusxanthin), were identical with those of synthetic (3R,3''S,6''S)-isomer 1d (6''-epigobiusxanthin) rather than those of the corresponding synthetic 3''-epi-isomer 1b. It was found that the stereochemistry at C3-position has little effect on the shape of their CD spectra. Thus, in order to reinforce the validity of the absolute configurations at C3-position of natural specimens, (3S,3''S,6''R)- and (3S,3''S,6''S)-stereoisomers 1e and 1f were also synthesized and a HPLC analytical method for four stereoisomers was established by using a column carrying a chiral stationary phase. The HPLC analysis has proven that the stereochemistry of the natural epigobiusxanthin is 3R,3''S,6''S.  相似文献   
10.
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